Create a DataUseRecorder instance for each page load in Chrome.

components/data_use_measurement/core/data_use_recorder.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/data_use_measurement/core/data_use_recorder.h"
 
 #include "net/url_request/url_request.h"
 
 namespace data_use_measurement {
 
-DataUseRecorder::DataUseRecorder() {}
+DataUseRecorder::DataUseRecorder() : main_url_request_(nullptr) {}
 
 DataUseRecorder::~DataUseRecorder() {}
 
 bool DataUseRecorder::IsDataUseComplete() {
   return pending_url_requests_.empty() && pending_data_sources_.empty();
 }
 
-void DataUseRecorder::OnBeforeUrlRequest(net::URLRequest* request) {
+void DataUseRecorder::AddPendingURLRequest(net::URLRequest* request) {
   pending_url_requests_.insert(request);
 }
 
 void DataUseRecorder::OnUrlRequestDestroyed(net::URLRequest* request) {
   pending_url_requests_.erase(request);
 }
 
+void DataUseRecorder::RemoveAllPendingURLRequests() {
+  pending_url_requests_.clear();
+}
+
+void DataUseRecorder::OnBeforeUrlRequest(net::URLRequest* request) {}
+
 void DataUseRecorder::OnNetworkBytesReceived(net::URLRequest* request,
                                              int64_t bytes_received) {
   data_use_.total_bytes_received_ += bytes_received;
 }
 
 void DataUseRecorder::OnNetworkBytesSent(net::URLRequest* request,
                                          int64_t bytes_sent) {
   data_use_.total_bytes_sent_ += bytes_sent;
 }
 
 void DataUseRecorder::AddPendingDataSource(void* source) {
   pending_data_sources_.insert(source);
 }
 
 bool DataUseRecorder::HasPendingDataSource(void* source) {
   return pending_data_sources_.find(source) != pending_data_sources_.end();
 }
 
 void DataUseRecorder::RemovePendingDataSource(void* source) {
   pending_data_sources_.erase(source);
 }
 
-bool DataUseRecorder::HasPendingURLRequest(const net::URLRequest* request) {
+bool DataUseRecorder::HasPendingURLRequest(net::URLRequest* request) {
   return pending_url_requests_.find(request) != pending_url_requests_.end();
 }
 
+void DataUseRecorder::MergeFrom(DataUseRecorder* other) {
+  data_use_.MergeFrom(other->data_use());
+}
+
 }  // namespace data_use_measurement